&nbsp&nbsp&nbsp&nbsp The two branches of security theory are centered around what one is trying to protect - a physical item or computer-held information.

&nbsp&nbsp&nbsp&nbsp In the case of a physical object, security is somewhat straightforward. The aim is to allow only authorized individuals access to the object you wish to protect. Therefore, one must offer no way for an unauthorized individual to access that object. Fences, guards, and closed-circuit cameras are clear ways of accomplishing this, though the ways in which they are implemented is crucial to their effectiveness. Of course, it is clearly impossible to achieve this level of security when one is trying to secure, say, the president of the United States when he is giving a speech outdoors in the middle of a city. For this reason, the Secret Service does not focus on sealing off the area, but instead looks for suspiciousbehavior in individuals in the surrounding area and removes them if necessary and also keeps an eye on nearby buildings for flashes of light (which could indicate a riflescope). This is called creating relative security. Relativesecurity is used to describe an area that is more secure under current security practices than it would be if lesser or no security measures were taken. Naturally, the president in this case is not even close to completely secure, but is much more secure than if he had no guards performing this task.

&nbsp&nbsp&nbsp&nbsp Computer security is far more complicated and specialized. This type of security deals primarily with data protection but encompasses many other niches of computing as well. Computer security began with encryption in WWII, as computers were developed, in part, to aid in the decryption of enemy transmissions. Today, encryption is accomplished in many ways, using complicated algorithms to scramble and obfuscate meaningful information into meaningless data that must be decrypted to be usable. Modern algorithms for encryption are so effective that the best ones could not be broken for millions of years (long enough to make said information meaningless by that time). Later in computer history the idea came about that one need not encrypt all the information one wishes to hide if only the people you want to see the information can access it. Hence the birth of password protection. While in theory this method of data protection is flawless, in practice there are many variables that may lead to a security breach. For instance, one of the individuals that has access to the data may leak his or her password to another, unauthorized individual. Computer-savvy persons may analyze the computer code that implements the password protection on a certain computer and find a flaw and use this to gain unauthorized access.